An immersive video content is a video content that is made to be displayed around a user, so that the user has the feeling to be in the middle of the content. Immersive video content is typically rendered in geodes or caves. In such apparatus, the content is entirely projected on wall screens and the user discovers the content by rotating his/her head.
Head-Mounted Displays (HMD) are display devices, worn on the head or as part of a helmet, that have a small display optic in front of one eye (monocular HMD) or each eye (binocular HMD). They are advantageously adapted to consume immersive content. In such a device, only a part of the video is displayed. The displayed part of the video content is updated according to the user head pose by the mean of an integrated Motion Unit Measurement (including a gyroscope) for instance.
Such devices were initially proposed some decades ago, but recently, due to the progress screens especially, their prices as well as their performances have been dramatically changed. The advent of such devices allows the user to watch a 4π steradians content by the mean of head rotations. If such a new feature may appear as a real improvement in terms of immersion in the content, as the user is watching at only a part of the content, he/she may not look at the direction he/she should look at a given moment. Indeed, as the user can gaze all around him/her, he/she may miss some important highlights of the narration because he/she is watching at another part of the content at the moment the narrative event happens.
According to the background art, it is known that forcing a virtual camera panning in order to make the user look toward the direction he/she has to look to, is a very efficient solution. However, it is well known that this solution has the drawback to make most of people sick and, as a consequence, to deteriorate the user's quality of experience.